Question

4 table. 4.1 shows part of a food label from a carton of eggs. table 4.1

nutrient	mass per 100 g of eggs / g
protein	13.6
sugar	0.5
starch	0.0

table 4.2 shows food tests carried out on an egg.
(a) complete table 4.2 by filling in the blank spaces.
table 4.2

nutrient tested	test carried out	result of test
protein
starch	add iodine solution	your black formed

(b) name an important nutrient, not listed in table 4.1 that is necessary in our daily diet.
state one function of this named nutrient.
nutrient
function

Explanation:

Part (a)

Fats Test:

Step1: Recall fat test method

The test for fats using ethanol: when we add a mixture of ethanol (where fat dissolves) and the food (egg) to water, fat will make the solution turn cloudy (emulsion formation).
So for fats: test is adding ethanol - food mixture to water, result is a cloudy white emulsion.

Protein Test:

Step2: Recall protein test (Biuret test)

The test for protein is adding Biuret reagent (or sodium hydroxide and copper sulfate solution). The result is a color change to purple (or violet) when protein is present (since eggs have protein, as seen in Table 4.1 with 13.6 g per 100g). So test: add Biuret reagent (or NaOH + CuSO₄), result: solution turns purple.

Starch Test:

Step3: Recall starch - iodine test

Starch test is adding iodine solution. From Table 4.1, starch in eggs is 0.0 g per 100g, so there is no starch. So when we add iodine solution, instead of blue - black, the result should be that the solution remains brown (or the color of iodine solution, no blue - black color change) because there is no starch. The original handwritten "your black formed" is incorrect; since starch is 0.0, the result is no blue - black (iodine remains brown).

Part (b)

Step1: Identify a missing nutrient

Table 4.1 has fat, protein, sugar, starch. Missing nutrients could be vitamins, minerals, water, dietary fiber. Let's take vitamin C (or calcium, iron, water, etc.).

Step2: State function of the nutrient

For vitamin C: function is to help in the repair and growth of tissues, or it is an antioxidant, or helps in iron absorption. For example, if we choose vitamin C:
Nutrient: Vitamin C
Function: Helps in the formation of collagen (a protein for skin, blood vessels, etc.) or boosts the immune system, or acts as an antioxidant to protect cells from damage.

Or if we choose water:
Nutrient: Water
Function: Acts as a solvent for chemical reactions in the body, or helps in transporting nutrients and waste products.

Or if we choose calcium:
Nutrient: Calcium
Function: Important for the development and maintenance of strong bones and teeth, or involved in muscle contraction and nerve function.

Final Answers (Filling Table 4.2 and Part (b) Example)

Table 4.2 Completion:

nutrient tested	test carried out	result of test
protein	add Biuret reagent (or sodium hydroxide and copper sulfate solution)	solution turns purple
starch	add iodine solution	iodine solution remains brown (no blue - black color change)

Part (b) Example:

Nutrient: Vitamin C
Function: Helps in collagen synthesis (or boosts immunity, etc.)

(Other valid nutrients and functions: e.g., Water - acts as a solvent; Calcium - strengthens bones; Iron - component of hemoglobin for oxygen transport)

Answer:

Part (a)

Fats Test:

Step1: Recall fat test method

The test for fats using ethanol: when we add a mixture of ethanol (where fat dissolves) and the food (egg) to water, fat will make the solution turn cloudy (emulsion formation).
So for fats: test is adding ethanol - food mixture to water, result is a cloudy white emulsion.

Protein Test:

Step2: Recall protein test (Biuret test)

The test for protein is adding Biuret reagent (or sodium hydroxide and copper sulfate solution). The result is a color change to purple (or violet) when protein is present (since eggs have protein, as seen in Table 4.1 with 13.6 g per 100g). So test: add Biuret reagent (or NaOH + CuSO₄), result: solution turns purple.

Starch Test:

Step3: Recall starch - iodine test

Starch test is adding iodine solution. From Table 4.1, starch in eggs is 0.0 g per 100g, so there is no starch. So when we add iodine solution, instead of blue - black, the result should be that the solution remains brown (or the color of iodine solution, no blue - black color change) because there is no starch. The original handwritten "your black formed" is incorrect; since starch is 0.0, the result is no blue - black (iodine remains brown).

Part (b)

Step1: Identify a missing nutrient

Table 4.1 has fat, protein, sugar, starch. Missing nutrients could be vitamins, minerals, water, dietary fiber. Let's take vitamin C (or calcium, iron, water, etc.).

Step2: State function of the nutrient

For vitamin C: function is to help in the repair and growth of tissues, or it is an antioxidant, or helps in iron absorption. For example, if we choose vitamin C:
Nutrient: Vitamin C
Function: Helps in the formation of collagen (a protein for skin, blood vessels, etc.) or boosts the immune system, or acts as an antioxidant to protect cells from damage.

Or if we choose water:
Nutrient: Water
Function: Acts as a solvent for chemical reactions in the body, or helps in transporting nutrients and waste products.

Or if we choose calcium:
Nutrient: Calcium
Function: Important for the development and maintenance of strong bones and teeth, or involved in muscle contraction and nerve function.

Final Answers (Filling Table 4.2 and Part (b) Example)

Table 4.2 Completion:

nutrient tested	test carried out	result of test
protein	add Biuret reagent (or sodium hydroxide and copper sulfate solution)	solution turns purple
starch	add iodine solution	iodine solution remains brown (no blue - black color change)

Part (b) Example:

Nutrient: Vitamin C
Function: Helps in collagen synthesis (or boosts immunity, etc.)

(Other valid nutrients and functions: e.g., Water - acts as a solvent; Calcium - strengthens bones; Iron - component of hemoglobin for oxygen transport)